Problem when opening files/projects with SDL STUDIO 2021

Hello, I'm having a problem with Studio 2021. I can't open any Studio project or file by double clicking from this morning. I don't get any error message and I can open them going through Studio directly. Also, I should say I received a file from a client this morning. It was an SDLXLIFF file but strangely my computer didn't recognize it. So, I chose "open with"/"Studio 2021". The problem is that now all the SDLXLIFF files have the same appearance as the Studio project. How could I fix that? I'm wondering if it's not because of that I can't open anything by double clicking. Could somebody help me please? Many thanks in advance!

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